Stretchable transfer conveyer method of stretching transfer conveyer and stretchable guide device for movable article

ABSTRACT

In a transfer conveyer wherein a pair of guide rails respectively provided with guide surfaces for guiding both side surfaces of a transferred article in a transfer direction are extended in the transfer direction and wherein flexible endless belts are provided for supporting lower surfaces at both sides of the transferred article, whose both side surfaces are guided on the guide surfaces, to transfer the transferred article in the transfer direction, a stretching mechanism is provided on one end portion of each guide rail to be stretchable in the transfer direction, a stretchable guide surface for defining a flat surface continuous and even with the guide surface regardless of any stretched position is formed at a facing surface of each stretching mechanism, and plural pulleys for circulatably supporting a part of the endless belt are provided on the facing surface of the stretching mechanism. Thus, the guide surfaces for guiding each side surface of the transferred article are formed continuously even when the end portion of the guide rail is stretched by the stretching mechanism.

TECHNOLOGICAL FIELD

The present invention relates to a transfer conveyer for transferringtransferred articles such as printed boards or the like with endlessbelts such as transfer belts or the like.

BACKGROUND ART

Heretofore, there has been known a transfer conveyer in which a pair ofguide rails respectively provided with guide surfaces for guiding bothside surfaces of a transferred article in a transfer direction areextended in the transfer direction and in which plural pulleys areprovided for circulatably supporting endless belts, which support bothside lower surfaces of the transferred article, to transfer the same inthe transfer direction. In an electronic component mounding apparatus orthe like with such a transfer conveyer, since plural transfer conveyersare juxtaposed with the space between two adjoining transfer conveyersbeing set to several millimeters, care must be taken so that apparatusare not brought into contact or collision with each other when installedor displaced for new building, the layout change or the like of thefacilities, and this results in making the work troublesome and taking along time. Another conveyer has also been known, in which in order tosolve this problem, end portions of the guide rails are made stretchableto be adapted easily for the displacement of the apparatus. For example,Japanese unexamined, published patent application 2000-142944 describesa stretchable transfer conveyer, in which a channeled portion is formedat an end portion of each of guide rails while another channeled portioncomplementarily insertable thereinto is formed at a mating end portionof each of adjuster guide rails and in which each adjuster guide rail isjoined with the end portion of each guide rail to be positionallyadjustable within an area in which both of the channeled portions arefitted in each other, so that protrusion portions of either one of thechanneled portions insertable mutually exist to function as guides forguiding the either side of the transferred article.

However, in the stretchable transfer conveyer described in the Japaneseunexamined, published patent application 2000-142944, although theprotrusions of either one of the channeled portions each fitted into theother resides in the transfer direction in the stretched state,clearances are made between the protrusions and the channels to bringabout discontinuity, and steps are made between the ends of theprotrusions of one of the guide rail and the adjuster guide rail and theends of the protrusions of the other guide rail. Thus, a problem arisesin that the transferred article cannot be guided smoothly. Further, inthe case of a transferred article thin in thickness like printed boardor the like, it has been difficult to provide the channeled portions atrespective ends of the guide rail and the adjuster guide rail within thethickness of the thin transferred article.

In particular, where printed boards are to be transferred, the clearancebetween each side surface of the printed board and a guide surfacetherefore is set to a range of 0.5 to 1 mm, and thus, it is necessarythat each guide surface be continuous and smooth over the entire lengthof the transfer conveyer. Since the printed board before reflowprocessing holds electronic components by means of the viscosity only ofsoldering paste, such printed board has to be transferred smoothlywithout suffering any shock. However, the prior art stretchable transferconveyer constitutes discontinuous guide surfaces and thus, isunsuitable for use in transferring such printed boards.

The present invention is made to solve the problems involved in theprior art and provides a stretchable transfer conveyer and a method ofstretching a transfer conveyer wherein guide surfaces for guiding sidesurfaces of a transferred article can be formed as continuous and evenflat surfaces even where an end portion of each guide rail is stretchedby a stretching mechanism.

DISCLOSURE OF THE INVENTION

In order to solve the aforementioned problems and in order to attain itsobject, the present invention in a first aspect provides a stretchabletransfer conveyer wherein a pair of guide rails respectively providedwith guide surfaces for guiding both side surfaces of a transferredarticle in a transfer direction are extended in the transfer directionand wherein flexible endless belts for supporting lower surfaces at bothsides of the transferred article, whose both side surfaces are guidedalong the guide surfaces, to transfer the transferred article in thetransfer direction are drivingly connected to a drive device and arecarried along plural rotational members to be circulated. The conveyorincludes a stretching mechanism provided at one end of each of the guiderails to be stretchable in the transfer direction; a stretchable guidesurface provided at a facing surface of the stretching mechanism andformed into a flat surface continuous and even with the guide surfaceregardless of the stretched position of the stretching mechanism; andplural rotational members provided on the facing surface of thestretching mechanism for circulatably supporting the endless belt.

With this construction, since the layout and the displacement ofapparatus can be done with the space from guide rails next thereto orthe like being widened by contracting the stretching mechanism providedon the end of each guide rail, the danger of contact or collision withany adjoining apparatus is minimized, so that work becomes easier toshorten work time. Then, the space between the adjoining transferconveyers can be adjusted to several millimeter wide by stretching thestretching mechanism in the state that the layout of plural apparatus iscompleted. At this time, since the stretchable guide surface being aflat surface continuous and even with the guide surface is formed at thefacing surface of each stretching mechanism regardless of any stretchedposition of each stretching mechanism, the transferred articletransferred by the endless belts can be guided smoothly at each of theboth side surfaces thereof along the guide surface and the stretchableguide surface.

Further, according to the present invention in a second aspect, in thestretchable transfer conveyer improved as aforementioned in the firstaspect, the stretching mechanism comprises an adjuster member mounted onan end of each guide rail to be movable in the transfer direction andprovided with an adjuster guide surface being a flat surface even withthe guide surface; and a complementary member insertable into a spacewhich is made between the guide surface of the guide rail and theadjuster guide surface of the adjuster member when the adjuster memberis moved in the transfer direction and provided with a complementaryguide surface for forming the stretchable guide surface together withthe adjuster guide surface.

With this construction, when the adjuster member mounted on the endportion of each guide rail is adjusted with respect to its position inthe transfer direction, the complementary member is inserted into thespace made between the guide surface of each guide rail and the adjusterguide surface of the adjuster member, whereby the complementary guidesurface formed on the complementary member and the adjuster guidesurface form the stretchable guide surface which is a flat surfacecontinuous and even with the guide surface. Thus, in addition to theaforementioned effects of the invention in the first aspect, it ispossible to provide the stretchable transfer conveyer simplified inconstruction and low in cost.

Further, according to the present invention in a third aspect, in thestretchable transfer conveyer improved as aforementioned in the secondaspect, the complementary member is mounted on the end of the guide railto be movable in a complementary direction intersecting with thetransfer direction with the complementary guide surface defining a flatsurface continuous and even with the guide surface; and the adjustermember and the complementary member are joined at respective jointsurfaces which are inclined relative to the transfer direction as wellas to the complementary direction whereby the adjuster guide surface andthe complementary guide surface are jointed along the respective jointsurfaces to define the stretchable guide surface as a continuous andeven flat surface.

With this construction, when the adjuster member mounted on the endportion of each guide rail is adjusted with respect to its position inthe transfer direction, the complementary member mounted on the endportion of each guide rail is moved in the complementary direction, andthe complementary guide surface formed on the complementary member isconnected to the guide surface of the guide rail and the adjuster guidesurface of the adjuster member through the flat surface even andcontinuous therewith. Thus, in addition to the aforementioned effects ofthe invention in the second aspect, it is possible in a simplifiedconstruction to make the smooth stretchable guide surface as the flatsurface continuous and even with the guide surface of the guide rail.

According to the present invention in a fourth aspect, in thestretchable transfer conveyer improved as aforementioned in the thirdaspect, the adjuster member has mounted thereon a first rotationalmember for winding therearound one end of a horizontally travelingportion of the endless belt and a second rotational member fordownwardly bending the endless belt run out from the first rotationalmember; the complementary member has mounted thereon a third rotationalmember for horizontally bending the endless belt run out from the secondrotational member and a fourth rotational member for roughly verticallybending the endless belt bent horizontally; and the guide rail hasmounted thereon a fifth rotational member for horizontally bending theendless belt run out from the fourth rotational member.

With this construction, when the adjuster member mounted on the endportion of each guide rail is adjusted with respect to its position inthe transfer direction, the first and second rotational members mountedon the adjuster member and the third and fourth rotational membersmounted on the complementary member are moved in dependence on themovement of the adjuster member. Thus, the endless belt can be supportedto be circulated with the end portion being hardly slacked. Thus, it canbe realized to minimize the slack or the like of the endless belt whenthe position adjustment is performed of the adjuster member.

According to the present invention in a fifth aspect, in the stretchabletransfer conveyer improved as aforementioned in the fourth aspect, thecomplementary direction is a vertical direction perpendicular to thetransfer direction; the adjuster member and the complementary member arejoined at the joint surfaces which are inclined 45 degrees relative tothe transfer direction; the adjuster guide surface and the complemehtaryguide surface are joined along the joint surfaces to constitute thestretchable guide surface; the adjuster member has mounted thereon thefirst rotational member for winding therearound one end of thehorizontally traveling portion of the endless belt and the secondrotational member for downwardly bending the endless belt run outhorizontally from the first rotational member; the complementary memberhas mounted thereon the third rotational member for horizontally bendingthe endless belt run out from the second rotational member and thefourth rotational member for roughly vertically bending the endless beltbent horizontally; the guide rail has mounted thereon the fifthrotational member for horizontally bending the endless belt run out fromthe fourth rotational member; and the third rotational member is movedas being restrained by a guide vertically provided on the adjustermember and another guide horizontally provided on the complementarymember.

With this construction, when the adjuster member mounted on the endportion of each guide rail is adjusted with respect to its position inthe transfer direction, the complementary member is moved by the sameamount in the vertical direction, and the third rotational member ismoved to cause portions of the endless belt running along the second tothe fourth rotational members to extend vertically and horizontallyregardless of any adjusted position of the adjuster member in thetransfer direction. Thus, it is possible to prevent the endless beltfrom being slacked even upon the movement of the adjuster member.

According to the present invention in a sixth aspect, the stretchabletransfer conveyers improved as aforementioned in the first aspect,further includes a feed device for moving the adjuster member in thetransfer direction; and means for moving the complementary member in thecomplementary direction in linkage relation with the movement of theadjuster member.

With this construction, when the end portion of the guide rail isstretched or contracted as a result of adjusting the position of theadjuster member by the feed device, the complementary member is moved inlinkage relation therewith to form the stretchable guide surface whichis the flat surface continuous and even with the guide surface. Thus, itis possible to stretch or contract the transfer conveyer by a simplifiedmanipulation. According to the present invention in a seventh aspect, inthe stretchable transfer conveyers improved as aforementioned in thefirst aspect, the transferred article is a printed board or a board formounting electronic components thereon.

With this construction, since the stretchable guide surface which is theflat surface continuous and even with the guide surface of each guiderail is formed at the facing surface of the stretching mechanismregardless of any stretched position of the stretching mechanism, it ispossible to smoothly transfer the thin printed board or the thin boardfor mounting electronic components thereon.

In an eighth aspect the present invention provides a method ofstretching a transfer conveyer wherein a pair of guide railsrespectively provided with guide surfaces for guiding both side surfacesof a transferred article in a transfer direction are extended in thetransfer direction and wherein flexible endless belts for supportinglower surfaces at both sides of the transferred article, whose both sidesurfaces are guided along the guide surfaces, to transfer thetransferred article in the transfer direction are drivingly connected toa drive device and are carried along plural rotational members to berecirculated. The method includes mounting an adjuster member, which isprovided with an adjuster guide surface being a flat surface even withthe guide surface, on one end of each guide rail to be movable in thetransfer direction; providing a complementary member, which is providedwith a complementary guide surface being a flat surface even with theguide surface, to be movable in the complementary direction intersectingwith the transfer direction with the guide surface and the complementaryguide surface defining a continuous and even flat surface; and joiningthe adjuster member and the complementary member at respective jointsurfaces which are inclined relative to the transfer direction and thecomplementary direction so that a stretchable guide surface is formed byjoining the adjuster guide surface and the complementary guide surfacealong the joint surfaces to define the continuous and even flat surface.

In this method, when the adjuster member mounted on the end portion ofeach guide rail is adjusted with respect to its position in the transferdirection, the complementary member is moved in the complementarydirection to be inserted into the space made between the guide surfaceof each guide rail and the adjuster guide surface of the adjustermember. Thus, the stretchable guide surface which is the flat surfacecontinuous and even with the guide surface of the guide rail can beeasily formed by means of the complementary guide surface and theadjuster guide surface formed on the complementary member and theadjuster member.

In a ninth aspect of the present invention, there is provided astretchable guide device for a movable article including a pair of guiderails respectively provided with guide surfaces for guiding both sidesurfaces of the movable article in a moving direction; an adjustermember mounted on one end of each of the guide rails to be movable inthe moving direction of the movable article and provided with anadjuster guide surface which is a flat surface even with the guidesurface; and a complementary member insertable into a space which ismade between the guide surface of the guide rail and the adjuster guidesurface of the adjuster member when the adjuster member is moved in themoving direction, and provided with a complementary guide surface forforming a stretchable guide surface together with the adjuster guidesurface.

With this construction, since the layout and the displacement ofapparatus can be done with the space from guide rails next thereto orthe like being widened by contracting the adjuster member provided onthe end of each guide rail, the danger of contact or collision with anyadjoining apparatus is minimized, so that it becomes easier to shorten awork time. Then, the space between the adjoining transfer conveyers canbe adjusted to several millimeter wide by stretching the adjuster memberin the state that the layout of plural apparatus is completed. At thistime, when the adjuster member mounted on the end portion of each guiderail is adjusted with respect to its position in the moving direction ofthe movable article, the complementary member is inserted into the spacemade between the guide surface of each guide rail and the adjuster guidesurface of the adjuster member, whereby the complementary guide surfaceformed on the complementary member and the adjuster guide surface formthe stretchable guide surface which is a flat surface continuous andeven with the guide surface, and the movable article can be smoothlyguide at each of its both side surfaces along the guide surface and theand the stretchable guide surface. Thus, it is possible to provide thestretchable guide device for the movable article simplified inconstruction and low in cost.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing a stretchable transfer conveyer ina first embodiment according to the present invention;

FIG. 2 is an enlarged perspective view showing the environment of astretching mechanism;

FIG. 3 is a perspective view showing the stretching mechanism in astretched state;

FIG. 4 is a view showing a tension pulley;

FIG. 5 is a view showing a second embodiment; and

FIG. 6 is a view showing a stretching mechanism in the second embodimentin a stretched state.

PREFERRED EMBODIMENTS TO PRACTICE THE INVENTION

Hereafter, a stretchable transfer conveyer in a first embodimentaccording to the present invention will be described with reference tothe drawings. In FIG. 1, a numeral 1 denotes a base of, e.g., anelectronic component mounting apparatus, and a pair of guide rails 2 aand 2 b are fixed on the base 1 to extend in the transfer direction inwhich transferred articles are to be transferred. Guide surfaces 4 forguiding both side surfaces of a transferred article such as printedboard or the like in the transfer direction are provided respectively atfacing surfaces 3 of the guide rails 2 a and 2 b. At the facing surface3 of each of the guide rails 2 a, 2 b, a flexible endless belt such asbelt 5, chain or the like for transferring the transferred article inthe transfer direction while supporting lower surfaces at both sides ofthe transferred article is supported to be circulatable by being woundaround plural rotational members such as pulleys or the like. Althoughthe guide rails 2 a, 2 b are arranged to be symmetrical with respect toa plane extending in parallel therebetween, they take the sameconstruction, and therefore, the following description will be maderegarding the guide rail 2 a only. A motor 7 as drive device is fixed onthe facing surface 3, and a toothed pulley secured on an output shaft ofthe motor 7 is in mesh with grooves formed on the internal surface ofthe belt 5 thereby to drive the belt 5. As shown in FIG. 2, ahorizontally traveling section of the belt 5 which section horizontallytravels along the guide surface 4 with its external surface directedupward is moved to make its internal surface slide along a support bar 8which is horizontally fixed on the facing surface 3 of the guide rail 2a.

Stretching mechanisms 10 are provided at respective one ends of theguide rails 2 a, 2 b. At the one end of the guide rail 2 a, the insidesurface 11 recedes outside from the facing surface 3 to form a thindepth portion 12. A T-shape protrusion 15 formed on a back surface of anadjuster member 14 is fit in a T-shape slot 13 horizontally provided onthe inside surface 11, so that the adjuster member 14 is mounted on theend portion of the guide rail 2 a to be adjustable with respect to itsposition in the horizontal direction coinciding with the transferdirection. A joint surface 16 inclined 45 degrees relative to thehorizontal direction is formed on the adjuster member 14 to facedownward, and a slot 17 is formed on the joint surface 16. The adjustermember 14 is provided with an adjuster guide surface 18 which is a flatsurface even with the guide surface 4.

A stepped portion 20 at an end of the thin depth portion 12 is formedperpendicularly to the guide surface 4 to extend in the verticaldirection, and a slot 21 is formed at the stepped portion 20 to extendin the vertical direction. The slot 21 has fitted therein a protrusion23 of a complementary member 22, and the complementary member 22 ismovable in the vertical direction coinciding with a complementarydirection. A joint surface 24 inclined 45 degrees relative to thehorizontal direction and the vertical direction is formed on thecomplementary member 22 to face upward, and a protrusion 25 is protrudedfrom the joint surface 24 to fit in the slot 17. The complementarymember 22 is provided with a complementary guide surface 26 which is aflat surface even with the guide surface 4. Thus, when the adjustermember 14 is moved horizontally, the complementary member 22 is moved inthe vertical direction by being guided through the fitting engagement ofthe slot 21 with the protrusion 23 as the adjuster member 14 and thecomplementary member 22 are guided through the fitting engagement of theslot 17 with the protrusion 25 to keep the contact at the joint surfaces16 and 24. As a result, the complementary guide surface 26 of thecomplementary member 22 is inserted into a clearance made between theguide surface 4 of the guide rail 2 a and the adjuster guide surface 18of the adjuster member 14, and the adjuster guide surface 18 and thecomplementary guide surface 26 are kept joined with each other along thejoint line between the joint surfaces 16 and 24, whereby a stretchableguide surface 27 is formed to be a flat surface continuous and even withthe guide surface 4.

A feed screw 28 is rotatably carried at its one end on a lower end ofthe adjuster member 14 without being moved relative to the adjustermember 14 in the axial direction thereof and is screw-engaged at itsscrew portion 29 with a female screw portion 30 protruded from a lowerend of the guide rail 2 a. Thus, the feed screw 28, the female screwportion 30 and the like constitute a feed device 31 for moving theadjuster member 14 in the transfer direction. Over the feed screw 28, aspring seat 32 is extended horizontally from the stepped portion 20 ofthe guide rail 2 a, and a compression spring 33 seated on the springseat 32 is received in a spring receiving hole which is formed upwardfrom a bottom surface of the complementary member 22, thereby to urgethe complementary member 22 upward. The compression spring 33, thespring seat 32 and the like constitute a linkage motion means 34 formoving the complementary member 22 in the complementary direction inlinkage relation with the movement of the adjuster member 14.

The both ends of the horizontally traveling section of the belt 5 whichsection travels on the guide surface 4 with its external surface facedupward are wound respectively around a pulley 6 a carried on an upperportion on the other side of the guide rail 2 a to be rotatable about ahorizontal axis and a first pulley 6 b mounted on an upper portion onone side of the adjuster member 14. The belt 5 run out horizontally fromthe first pulley 6 b is bent downward by a second pulley 6 c mounted onthe adjuster member 14, the belt 5 run out from the second pulley 6 c isbent horizontally by a third pulley 6 d mounted on the complementarymember 22, the belt 5 run out from the third pulley 6 d is bentvertically by a fourth pulley 6 e mounted on the complementary member22, the belt 5 run out from the fourth pulley 6 e is bent horizontallyby a fifth pulley 6 f mounted on an upper portion adjacent to thestepped portion 20 of the facing surface 3 of the guide rail 2 a, andthe belt 5 run out from the fifth pulley 6 f is wound around the pulley6 a after being caused by pulleys 6 g and 6 h to be wound around thetoothed pulley secured to the output shaft of the motor 7.

When the position of the adjuster member 14 is adjusted in thehorizontal direction, the distance through which the belt 5 is woundaround the pulleys 6 would otherwise become different from the length ofthe internal surface of the belt 5. To cancel the difference, as shownin FIG. 4, an elongate groove 35 is formed on the adjuster member 14 toextend in the horizontal direction, the second pulley 6 c is rotatablycarried on a horizontal shaft 37 which is provided on a slider 36 heldslidably in the elongate groove 35, and the slider 36 is urged by acompression spring 38, whereby the second pulley 6 c functions as atension pulley to give a suitable tension to the belt 5 between thefirst and third pulleys 6 b, 6 d.

Next, description will be made regarding the operation of the conveyerin the foregoing first embodiment. Where the facility is newly built upor is changed for new layout, the adjuster members 14 are bought intothe state that they are withdrawn relative to the guide rails 2 a and 2b, and an apparatus next to the transfer conveyer is displaced andinstalled with a sufficient space being secured between the end portionof the transfer conveyer and the apparatus next thereto. With the layoutof the apparatus fixed, the feed screw 29 is rotated, and positionadjustment is performed by pulling out each of the adjuster members 14horizontally from the ends of the guide rails 2 a and 2 b through thescrew engagement of the screw portion 29 with the female screw portion30 so that the space from a transfer conveyer next thereto becomesseveral millimeter long. As each adjuster member 14 is movedhorizontally, the complementary member 22 is moved by the resilientforce of the compression spring 33 upward in the vertical direction withthe contact being kept between the joint surface 16 and the jointsurface 24, as shown in FIG. 3. Thus, the complementary guide surface 26of the complementary member 22 is inserted into the space made betweenthe guide surface 4 of the guide rail 2 a and the adjuster guide surface18 of the adjuster member 14, and the adjuster guide surface 18 and thecomplementary guide surface 26 are joined along the joint line betweenthe joint surfaces 16 and 24, whereby the stretchable guide surface 27is formed as the flat surface continuous and even with the guide surface4. At this time, the change in distance among the pulleys 6 caused bythe movement of the adjuster member 14 is cancelled through the movementof the second pulley 6 c. When the motor 7 is driven in this state, thebelt 5 is circulated while being guided along the pulleys 6, and thetransferred article which is mounted on the horizontally travelingsection of the belt 5 sliding on the support bar 8 is transferredsmoothly by being smoothly guided at its either side surface along theguide surface 4 formed at the facing surface 3 of each guide rail 2 a(or 2 b) as well as along the stretchable guide surface 27 of thestretching mechanism 10 which is formed as the flat surface even andcontinuous with the guide surface 4 without forming any stepped portion.

Second Embodiment

Next, description will be made regarding a stretchable transfer conveyerin a second embodiment wherein the third pulley 6 d is movable whilebeing restrained to slide along a vertical guide vertically provided onthe adjuster member 14 and a horizontal guide horizontally provided onthe complementary member 22. Because the conveyer in the secondembodiment has the same construction as that in the first embodimentexcept for a difference only in the manner of supporting the thirdpulley 6 d, the components of the second embodiment which are same asthose in the first embodiment are given the same reference numerals asused in the second embodiment and are omitted from description. As shownin FIGS. 5 and 6, the adjuster member 14 is provided with a hangingportion 40 which extends downward at a position close to the secondpulley 6 c, and a guide slot 41 is vertically formed on the hangingportion 40. An elongate guide hole 42 is formed on the complementarymember 22 to extend horizontally on the same position in the verticaldirection as the fourth pulley 6 e. A slider which protrudes ahorizontal shaft 43 rotatably carrying the third pulley 6 d is slidablyfit in the guide slot 41 and the elongate guide hole 42. Thus,regardless of any adjusted position of the adjuster member 14 in thehorizontal position, the belt 5 run out horizontally from the firstpulley 6 b is bent perpendicularly by the second pulley 6 c mounted onthe adjuster member 14 to run downward, and the belt 5 run outperpendicularly from the second pulley 6 c is bent by the third pulley 6d to run horizontally. Since the joint surfaces 16 and 24 are inclined45 degrees relative to the horizontal direction as well as to thevertical direction, the complementary member 22 is vertically moved bythe same distance as the moving distance in the horizontal direction ofthe adjuster member 14. At this time, the change of the belt windingdistance (L) which corresponds to twice as long as the moving distancein the horizontal direction of the adjuster member 14 is cancelled bythe change of the belt winding distance which corresponds to twice aslong as the same moving distance in the vertical direction of thecomplementary member 22, so that the winding distance around the pulleys6 does not vary regardless of any adjusted position of the adjustermember 14.

In the foregoing embodiments, the complementary direction is thevertical direction, and the joint surfaces of the adjuster member andthe complementary member are inclined 45 degrees relative to thetransfer direction as well as to the complementary direction. However,the present invention is not limited to this construction. In analternative form, there may be taken any other arrangement so far as thecomplementary direction is set to across the transfer direction and sofar as the joint surfaces are inclined relative to the transferdirection as well as to the complementary direction.

INDUSTRIAL APPLICABILITY

The stretchable transfer conveyer and the method of stretching thetransfer conveyer according to the present invention is suitable for useas a transfer conveyer for transferring printed boards to position thesame at a mounting position in an electronic component mountingapparatus wherein a component pickup head provided on a componentmounting device takes electronic components from a takeout portion of acomponent supply device to mount the electronic components on theprinted boards successively positioned to a target position.

1. A stretchable transfer conveyer for a transferred article comprisinga board, wherein a pair of guide rails respectively provided with guidesurfaces for guiding both side surfaces of the transferred article in atransfer direction are extended in the transfer direction and whereinflexible endless belts for supporting lower surfaces at both sides ofthe transferred article, both side surfaces of which are guided alongthe guide surfaces, to transfer the transferred article in the transferdirection, are drivingly connected to a drive device and are carriedalong plural rotational members to be circulated, the conveyercomprising: a stretching mechanism provided at one end of each of theguide rails to be stretchable in the transfer direction; a stretchableguide surface provided at a facing surface of the stretching mechanismand formed into a flat surface continuous and even with the guidesurface regardless of the stretched position of the stretchingmechanism; and plural rotational members provided on the facing surfaceof the stretching mechanism for circulatably supporting the endlessbelt, wherein the stretching mechanism comprises: an adjuster membermounted on an end of each guide rail to be movable in the transferdirection and provided with an adjuster guide surface being a flatsurface even with the guide surface, and a complementary member insertedinto a space which is made between the guide surface of the guide railand the adjuster guide surface of the adjuster member when the adjustermember is moved in the transfer direction, and provided with acomplementary guide surface for forming the stretchable guide surfacetogether with the adjuster guide surface, and wherein the complementarymember is mounted on the end of the guide rail to be movable in acomplementary direction intersecting with the transfer direction withthe complementary guide surface defining a flat surface continuous andeven with the guide surface, and the adjuster member and thecomplementary member are joined at respective joint surfaces which areinclined relative to the transfer direction as well as to thecomplementary direction, whereby the adjuster guide surface and thecomplementary guide surface are jointed at the respective joint surfacesto define the stretchable guide surface as a continuous and even flatsurface.
 2. The stretchable transfer conveyer as set forth in claim 1,wherein: the adjuster member has mounted thereon a first rotationalmember for winding therearound one end of a horizontally travelingportion of the endless belt and a second rotational member fordownwardly bending the endless belt run out from the first rotationalmember; the complementary member has mounted thereon a third rotationalmember for horizontally bending the endless belt run out from the secondrotational member and a fourth rotational member for roughly verticallybending the endless belt bent horizontally; and the guide rail hasmounted thereon a fifth rotational member for horizontally bending theendless belt run out from the fourth rotational member.
 3. Thestretchable transfer conveyer as set forth in claim 2, wherein: thecomplementary direction is a vertical direction perpendicular to thetransfer direction; the adjuster member and the complementary member arejoined at the joint surfaces which are inclined 45 degrees relative tothe transfer direction; the adjuster guide surface and the complementaryguide surface are joined along the joint surfaces to constitute thestretchable guide surface; the adjuster member has mounted thereon thefirst rotational member for winding therearound one end of thehorizontally traveling portion of the endless belt and the secondrotational member for downwardly bending the endless belt run outhorizontally from the first rotational member; the complementary memberhas mounted thereon the third rotational member for horizontally bendingthe endless belt run out from the second rotational member and thefourth rotational member for roughly vertically bending the endless beltbent horizontally; the guide rail has mounted thereon the fifthrotational member for horizontally bending the endless belt run out fromthe fourth rotational member; and the third rotational member is movedas being restrained by a guide vertically provided on the adjustermember and another guide horizontally provided on the complementarymember.
 4. The stretchable transfer conveyer as set forth in claim 1,further comprising: a feed device for moving the adjuster member in thetransfer direction; and means for moving the complementary member in thecomplementary direction in linkage relation with the movement of theadjuster member.
 5. A method of stretching a transfer conveyer for atransferred article comprising a board, wherein a pair of guide railsrespectively provided with guide surfaces for guiding both side surfacesof the transferred article in a transfer direction are extended in thetransfer direction and wherein flexible endless belts for supportinglower surfaces at both sides of the transferred article, both sidesurfaces of which are guided along the guide surfaces, to transfer thetransferred article in the transfer direction, are drivingly connectedto a drive device and are carried along plural rotational members to berecirculated, the method comprising: mounting an adjuster member, whichis provided with an adjuster guide surface being a flat surface evenwith the guide surface, on one end of each guide rail to be movable inthe transfer direction; providing a complementary member, which isprovided with a complementary guide surface being a flat surface evenwith the guide surface, to be movable in the complementary directionintersecting with the transfer direction, with the guide surface and thecomplementary guide surface defining a continuous and even flat surface;joining the adjuster member and the complementary member at respectivejoint surfaces which are inclined relative to the transfer direction andthe complementary direction so that a stretchable guide surface isformed by joining the adjuster guide surface and the complementary guidesurface along the joint surfaces to define the continuous and even flatsurface; and moving the complementary member in the vertical directionwhen the adjuster member is horizontally moved in the transferdirection.
 6. A stretchable guide device for a movable articlecomprising a board, comprising: a pair of guide rails respectivelyprovided with guide surfaces for guiding both side surfaces of themovable article in a moving direction; an adjuster member mounted on oneend of each of the guide rails to be movable in the moving direction ofthe movable article and provided with an adjuster guide surface which isa flat surface even with the guide surface; a complementary memberinserted into a space which is made between the guide surface of theguide rail and the adjuster guide surface of the adjuster member whenthe adjuster member is moved in the moving direction, and provided witha complementary guide surface for forming a stretchable guide surfacetogether with the adjuster guide surface; and a mechanism for moving thecomplementary member in the vertical direction when the adjuster memberis horizontally moved in the transfer direction.
 7. The stretchabletransfer conveyer as set forth in claim 6, further comprising: flexibleendless belts for supporting lower surfaces at both sides of the movablearticle, wherein the adjuster member and the complementary member arejoined at the joint surfaces which are inclined by 45 degrees relativeto the transfer direction, and the complementary member rotatablysupports at least two rotational members for bending a returning part ofthe flexible endless belt in a U-shape, whereby when the adjuster memberis adjusted a given distance horizontally in the transfer direction, thecomplementary member is moved by the moving mechanism by the samedistance to automatically maintain the tension of the flexible endlessbelts unchanged.